# Geometry – Logic Stuff

I’m totally reducing the amount of time I spend on this next year. But I’m blogging out what I did just in case you teach it as well.

Things I liked (in order that I taught it):

Inductive and Deductive reasoning sort – I made a card sort with inductive and deductive reasoning examples.  I had the kids sort the cards with zero information, then tell me what they felt was different about the two sets of cards.  They did a great job!  I’m not including my cards because I need to change them next year.  I will only do words on both types of cards, and no patterns or numbers.  A few students took inductive to mean “numbers” or patterns only, and deductive to mean “words”.

I need to spend more time turning statements into conditional statements.

Conditional / Converse / Inverse / Contrapositive Activity from Sam and the great folks at PCMI.  Wow – what a great activity!!  TIPS:

• It takes a few days but it is worth it!  All students were very engaged the entire time.
• DON’T LET THE STUDENTS WRITE THEIR OWN STATEMENTS.  Use the ones Sam etc. wrote.  You will thank me later.
• It is “paper intensive” so make group packets before they come in to preserve your sanity.
• I put the directions in a picture frame so students could see it more easily as it is a “directions intensive” activity.  They did well and I love when they practice following directions.
• After the posters were all finished, I had students do a “gallery walk” with post-its so they could make comments on other posters in case a student got the truth value incorrect.  This was great!

Symbolic Logic Proofs – I made cards for them to refer to.  They used them often.  We made “index card pockets” in their graph books to hold them.  I loved these things!

Proof strips – I laminated card stock and we wrote on these to re-arrange the statements.

Post-it flags – I also let them use post-it flags to write the givens on so they could be easily rearranged.

I also combined this with Speed Dating for the win.  I don’t think I can ever thank Kate enough for Speed Dating.

I did another sorting activity thanks to Pam Wilson’s intro to logic post.  This went well!   I let them sort on the floor if they wanted and then check their answers with another group.

## 6 thoughts on “Geometry – Logic Stuff”

1. You are a freakin’ rock star Julie! Where do you find the time to do all of this stuff and plan all of these awesome lessons for your students? Like always, I’ll be stealing this later! Thanks for all that you do for your students and other teachers!

• Haha. That’s so nice of you to say! This year has been hectic. I don’t sleep nearly enough and haven’t been blogging. But, I don’t have a choice, I just do not like to lecture. 🙂

2. Julie, you remind me of my golden past the school days, logic and compatibility was like a nightmare for me and I was like stuck in p q and r. My teachers really help me in understanding all this, but overall it was fun.

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4. I have a question
How can I divid the irregular shapes into two halves by connect the two points on the irregular shapes?

5. great collection of activities. Thank you for sharing!
Questions since a year has gone by since you wrote this post:
1.Did you redo your cards for the inductive deductive sort? How was the improved activity?
2.Did you shorten as you said you might? If so, what did you cut?